The conventional method for forging and quenching metal involves a first step in which a metal material is heated at a temperature as high as 1100.degree. C. for 30 minutes. The heat-treated metal is then forged. The forged metal is then cooled before it is subjected to heating at a temperature ranging between 880.degree. C. and 950.degree. C. The forged metal is cooled suddenly by plunging into oil. The quenched metal is finally tempered.
The conventional forging and quenching method described above is generally defective in design in that the heating duration is too long, and that the oil burning furnace used in heating tile metal is a culprit for air pollution, and further that the quality of the metal so treated is unduly compromised, and still further that the method is not cost-effective.